Electrical apparatus



P ,1 1- D. MULLER-HILLEBRAND ET AL- 2,255,926

ELECTRICAL APPARATUS Filed Feb. 18, 1939 d T m 5 rs k ma M m D 9 7 u 0 a 1 u 1 w v B) I/ m "H" a M 1 2. m

Insulation Wham WITNESSES @w W Patented Sept. 16, 1941 'FEQE ELECTRICAL APPARATUS Dietrich Miiller -Hillebrand, Halensee, and Max Proschmann. Siemensstadt. Germany, assign"- ors toWcstinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,- a corporation of Pennsylvania Application February-18, 1939; SeriaPNo. 2575154 In .Germany- February" 19, 1938 8 Claims. 31. 200-163) This invention relates to improvements in electrical apparatus and more particularly to high current carrying'devices in the-form of bus bar structures, fuses, switches and the. like. Heretofore considerable difficultyhas beenencountered-in securing low resistance contacts between separable sections or parts oi an electrical conducting system due-to misalignment of 1 the cooperating contact surfaces.- Inpractice, the" contact surfaces is renderedmore' complex" in electrical systems designed tojcarr-y 1arge-cur-- rents due to the requirement of conductors of large cross-section which consequently possess considerable'rigidity. Conductor rigidity, how-'- ever, is desirable from the standpoint thatit ofiers self-support.

It is, therefore, an object of. thiszinvention to provide a conducting member for high current electrical apparatus which possesses the desired rigidity to be self-supporting, butwhich has a flexibility such that portions thereof are readily made to engage and'cooperate with an associated contact surface.

Another object of this invention is to effect. a. saving in material used in electrical apparatus by...

increasing the current carrying. capacity of the conducting members without increasing the cross:- sectional area and withoutflimpairing the longitudinal rigidity of the conducting. members.

A more specific object of the invention-istheprovision of cooperating contact members -for electrical apparatus, at least-one of which is ren-' dered flexible to a degree to enableitto readily conform to the-contour of the other member.

Other objects and advantages relate to the particular structures for carrying out our invention and will appear morefully inthe:-following de'- scription when read inconne'ction' with" the: ac

companying drawing, in which: V

Figure l is a side elevational view showing theprinciples oi our invention applied to"- a fuse structure;

Fig. 2 is an end view of the. fuse structure shown in Fig. 1;

end views of a modified form of contact structureembodying the principles of our invention.

Referring-to Figs. 1 and 2- of the drawing, the reference numeral 'ldesignates a cartridge fuse having a cylindrical body portion 9 of insulating. material and a pairof metalli'ccollars or ferrules l ldisposed on opposite ends thereof. Each of the ferrules I i has a corrugated blade projection l3 extending therefrom. Theblade projections I3 are adapted tobe seated between a pair of sp'acedparallel plate-members ll constituting acontact jaw I9. Each-contact jaw l9is provided witha threaded terminal Stud 22! whichserves, to a secure the contactjaws to: an insulating panel 23,- a.nd'-also provides a terminal for external circuit connections;

The electrical circuit between the two metallic ferrules ll is com'pleted .by' a fusible element of conventional'fc'rm (not shown) within the cylin drical body portion 9i It should be noted that the blade projections 13 are of corrugated form which provides a-series of linec'onta'ctsbetween the'bladep'ortions l3 and the plate membersll of the contact jaws l9: The blade portions 13 may, therefore; be constructed of relatively thin flexible-material without impairing the rigidity thereof in a direction atright angles to the corrugations. The corrugated structure, however, does not impair I the torsional-flexibilityof'the blade portions is;

so that these portions are free to conform themselves to the engageab-l'econtact surfaces of the jaw' members 53 irrespectiveoi the alignment within predetermined limits of the jawmembers;

; The grooved or corrugated form of blade member incre'asesthe current carrying capacity of the member in that it provides greater surface area for cooling purposes for a given external dimension'.

, Obviously'when a blade'portion' I3 is inserted between-the relatively'rigid plate members ll of the'cont'actjaws l9, and since the blade portions l3-are designed tafit tightly between the plate members upon insertion of th'e'bladeportions Fig. 3 is an elevation view showingour inv'ention embodied in a disconnect switch structure;

Fig. 4 is an end view of thestructure sl'iown in Fig. 3;' and Figs. 5 and 6 are, respectively,- elevational 'an'd it; the corrugations'thereof will tend to befiatten-ed out to-provide a plurality of spaced line contacting'portio'ns under pressure. In-the event there'a're'ariy irregularities 'or'une'venness in the inner contact'sririac'e's of' the plate members H,

such defects will be compensated for by virtue of the factthat 'c'e'r-tainTcf the corrugations will then be fiattene'd out morefthan other will provide, "witainj certain-limits,- for a substantialline contactportion at each: corrugations.

i This: action of the blade through suitable dies.

In Figs. 3 and 4 the principles of our invention are shown applied to a disconnect switch consisting of a pair of contact terminals 21 and 29 mounted upon spaced insulators 3| and 33. The

' insulators 3| and 33 may be carried by a suitable base or support 35.- The contact terminals 21 and 29 are bridged by a pair of blade elements 31, and are preferably hinged to the contact terminal 29 by the bolt 39 passing therethrough.

Each of the blade elements 31 are preferably of,

corrugated form, as shown, and are drawn into We claim as our invention: 1. In electrical apparatus, an elongated flexible bridging member of a thickness which is contacting engagement with the contact terminal. 29 by the bolt 39 and the washers 4|. The blades 31 also make contacting engagement on opposite manner to the blade elements and provided at its outer end with an aperture 49 for the reception of a'hookstick, by which means the switch may be manually operated. 1 7

Fro'mithe foregoing it is clear that the corrugated" form of blade elements 3'! provides a switch blade structure which has the requisite rigidity longitudinally of the blade elements, and also" sufiicient' torsional flexibility to enable the blade elements to make a series of line contacts small as compared with its width and which has at least one side thereof longitudinally grooved for increasing its torsional flexibility about a longitudinal axis and for providing at least one convex limited area contact surface.

12. In a circuit making and breaking device, a

'pair of spaced contact means, and a movable bridging member of flexible material for interconnecting said spaced contact means, said bridging member having sinuous contact por- 'tions for engaging'said contact means, to rigidify with the contact terminals 21 and 29. Thus in the event that the contact terminals 21 and 29 should become displaced so as to be out of alignment, the misalignment within predetermined limits will not prevent the obtaining of a good contact between the blade elements and the contact terminals. V In Figs. 5 and 6 a further application of our invention is shown, and comprises a corrugated.

blade-like contact member 5I'carried by a stationary support 53. A movable contact having aibifurcated portion 51 is adapted to make sliding engagement with the stationary contact member 5|. Movement of the contact member 55 into and out. of engagement with the stationary contact 5| may take place longitudinally of the member 55 or in a direction at right angles to the longitudinal axis thereof. stance, as set forth in the previous illustrations,

the corrugated cont'actblade is flexible about an axis parallel to the corrugations so as to provide a series of line contacts with the cooperating contact surfaces.

The corrugated blade elements I3, 31 and 5| described in connection with the several figures i of the drawing, may be formed of conducting;

material in any suitable manner as, for example; by bending, rolling or drawing sheet material of suitable. thickness or extruding the metal In instances where the;

saving of material and the cost of production is of minor importance the corrugated conductors may be formed by machining slots or grooves in conductors of regular form. V Although' we have shown and described several specific applications of our invention, it is;

In this in- .the entireflen gth thereof to provide a torsionally flexible bridging member about a longitudinal j said contact portions at least in one direction but being flexible in at least another direction to provide a more accurate alignment between said contact portions and said contact means. 3. Ina circuit making and breaking device, a

pair' of spaced'contact means, a'relatively thin flexible blade member normally connecting said contact means and movable into and out of engagement with at least one of said contact means, said blade member being corrugated longitudinally throughout the width thereof on at 5 least one side for providing-torsional flexibility of said blade member about :a longitudinal axis, and" increasing the rigidity of said blade memher in a direction at right'angles to the corruga- ,g

tions, g

4. A circuit making 'and'breaking device comprising a pair of spaced terminals, a pair of blade elements hinged to oppositesides of oneofsaid:

terminals for swinging movement intoand out "of engagement with the other terminal, and;

means for clam-ping said blade elements into engagement with said other terminal, said blade elements having. longitudinally extending slots for rendering said elements torsionally: flexible :about alongitudinalaxis to enable said clamping means to align the blade elements with said other terminal. 1 1

5. A circuit'making and breaking device come prising a pair of spacedterminals, a pair .of blade elements ,hinged on opposite sides to one ofsaidterminals for swinging movementinto and out, of engagement with the other terminal, and means drawing said blade elements toward each other into contacting engagement with the opposed sides of said terminals, said blade elements being corrugated throughout their length to provide a series of substantially line contacts with the opposed sides of saidterminals.

6. In. electrical apparatus, a current carrying I elongated flexible bridging member having longitudinal corrugations extending substantially axis, but which is substantially rigid with respect to a forceapplied to said bridging member in the plane of said corrugations andat an angle thereto.

7. In electrical apparatus, a thin flexible current carrying'bridging member having rounded corrugations on opposite sides thereof to stiffen the. same and provide'a plurality of's-paced substantially linecontact portions at each end,

' thereof. 1

to;be understood that the same are for the purj pose ofillustration, and that we do not wish to, ;,be 'limited. therebylexcept as set forth in the appended claims. Y

8. In electrical apparatus, apair of spaced terminal members, each of said members-having a contact jaw,*each contact jaw comprising; a pair of relatively rigid spaced parallel plate members, anelongated bridging member having cooperating relatively thin contactg surfaces, h chare ap d-tec nser d be both pairs of said spaced parallel plate members to complete an electrical circuit through said terminal members, said relatively thin contact surfaces having a plurality of spaced longitudinal slots for increasing the torsional flexibility thereof about a longitudinal axis to provide for a more intimate contact between the contact surfaces of said bridging member and said contact jaws despite contact surface irregularities and misalignment of said contact jaws.

DIETRICH MULLER-HIILEBRAND.

MAX PROSCHMANN. 

